This invention relates generally to hazardous waste removal vacuum systems and more particularly to an improved filter module to protect the HEPA filter in the waste removal vacuum system.
Numerous prior art waste removal systems have been utilized for a considerable period of time for removing waste from a closely defined work area in which the contaminants or hazardous wastes are confined. The worker is protected from the wastes in various manners, since the wastes are confined inside of the system and the worker works in the system, but avoids direct contact with the wastes, for example, by utilizing the well-known glove bag concept.
One particular application for glove bag waste removal systems is in removing coatings or insulation from pipes which material is or contains asbestos. The prior art glove bags are secured and sealed around the pipes at the tops of the bags, such as by wrapping the open ends of the bag top around the pipe and taping the openings shut. The bags are utilized to remove the asbestos material and then are removed from the pipe and sealed for disposal. Typically, the bags are placed in a second bag for disposal. The bags and other removal systems are utilized under negative pressure and typically include one or more openings for vacuum lines and for water spray lines or nozzles for wetting down the material as an extra safety precaution.
Two somewhat related glove bag waste removal systems and applications are disclosed in application Ser. No. 001,074, entitled "Hazardous Waste Glove Bag Removal System" and Ser. No. 001,075, entitled "Glove Bag Waste Removal System For Asbestos Impregnated Brakes", both filed Jan. 7, 1987, the disclosures of which are incorporated herein by reference.
In the prior art, the vacuum systems which achieve the negative pressure, typically contain an expensive HEPA or HEPA-type filter. The HEPA-type filters are very heavy duty and can be utilized to pull 80-120 inches of water column of vacuum. The filters are intended for utilization with wet or dry material, however, the moisture added to the hazardous material, such as insulation, can clog the filters. If the filter is clogged, the filter can be blown out. This causes several problems, since the filters are expensive and because the hazardous materials can be released into the environment. The HEPA-type filters therefore are very expensive because they are constructed to withstand a very high pressure differential on the order of 20-30 inches of water column of vacuum, to prevent their collapse. Additionally, some of the prior art wet HEPA-type filter systems utilize float valves to try to prevent the water reaching the filter. The filters also typically are an integrated part of a special vacuum apparatus, which also adds an additional cost to the waste removal system.
It therefore would be desirable to provide a waste removal vacuum system, which can utilize the HEPA-type filter, but which is not easily clogged and also provides a structure which is durable and has a long use life. Further, the use of a conventional vacuum source would also be desirable to further decrease the system cost.